The present invention relates to a data transfer control device and an electronic instrument.
In recent years, a high-speed serial transfer interface such as a low voltage differential signaling (LVDS) interface has attracted attention as an interface aiming at reducing EMI noise or the like. In such a high-speed serial transfer, data is transferred by causing a transmitter circuit to transmit serialized data using differential signals and causing a receiver circuit to differentially amplify the differential signals (JP-A-2001-222249).
An ordinary portable telephone includes a first instrument section provided with buttons for inputting a telephone number or a character, a second instrument section provided with a main liquid crystal display (LCD), a sub LCD, or a camera, and a connection section (e.g. hinge) which connects the first and second instrument sections. Therefore, the number of interconnects passing through the connection section can be reduced by transferring data between a first substrate of the first instrument section and a second substrate of the second instrument section by serial transfer using differential signals.
It is desirable that the transfer efficiency be high when transferring data through the connection section by serial transfer. In particular, when displaying a motion picture on the LCD, it is desirable that packets from a host (first instrument section) be continuously transmitted to a target (second instrument section).
A display driver which drives a display panel such as an LCD may generate a vertical synchronization signal (VCIN) for indicating a non-display period of the display panel. For example, a display driver including a RAM controls switching between the non-display period and the display period of the display panel. Therefore, since the display driver must notify the host of the non-display period of the display panel, the display driver outputs the vertical synchronization signal to the host. Therefore, when realizing data transfer through the connection section between the first and second instrument sections by serial transfer, it is important to efficiently transmit the vertical synchronization signal output from the display driver to the host.